Memory cards such as SD memory card and multi media card (MMC) are becoming increasingly common in digital cameras, laptop computers and mobile phones, which place importance on portability and power consumption. In addition, as these electronic appliances are further downsized, a thinner compact mini memory card such as mini SD memory card is proceeding toward commercialization. To use such a mini memory card in an electronic appliance having a slot for a conventional regular-sized memory card, an adaptor is needed, which can accommodate the mini memory card therein, and be electrically and mechanically connected to the slot for the regular-sized memory card.
For example, Japanese Patent Early Publication [kokai] No. 11-3405 discloses an adaptor used to connect a memory card to a slot for another standard memory card. This adaptor is mainly composed of a frame with a pair of arms and a coupling piece, circuit board having a conductive pattern, and a pair of upper and lower metal covers. The frame is a synthetic resin product manufactured by injection molding. The circuit board is formed by printing a wiring pattern on an insulating material such as a phenol resin. One end of the conductive pattern is electrically connected to a plurality of terminals of the memory card inserted in the adaptor, and the opposite end of the conductive pattern is electrically connected to a plurality of terminals of the electronic appliance when the adaptor is inserted in the memory card slot. The frame mounting the circuit board thereon is held between the metal covers.
In this adaptor, the memory card is supported by the pair of arms of the frame made of a resin material. Although the arms are reinforced by the upper and lower metal covers, warpage or deformation of the arms of the resin material easily occurs. For example, when it is used as an adaptor for a thin mini memory card, the mini memory card may be damaged. In addition, since surfaces other than both side limbs of the memory card inserted in the adaptor are exposed, there is a fear that the exposed surfaces are grasped by mistake to eject the adaptor from the slot of the electronic appliance. In such a case, the thin mini memory card may be damaged. Thus, the conventional adaptor structure is not sufficiently considered as the adaptor for the thin compact mini memory card in view of its rigidity, and therefore has still plenty of room for improvement.